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changed cams......pops out the exhaust now
Posted By: E85-408
changed cams......pops out the exhaust now - 09/11/10 09:03 PM
Went from a hyd. to solid flat tappet cam(440). Easy swap did it before no problems just had to get different length pushrods to match the cam. Lunati cam 3 bolt with the correct comp cams 3 bolt timing chain. Put it on dot to dot nothing strange came up. Took abit longer to start but fired but had really bad popping out the exhaust. I played with timing over and over still the same. Went through all the lash again per cam in structions still no change. Checked for any type of vaccum leak, couldnt find anything. Did a complete compression test all cylinders were 175-160psi. Tore it all back down making sure I had the timing chain on right 3 different times and still the same popping. When its running higher rpms it doesnt smooth out. I checked all header tubes with a heat gun all cylinders firing. Also when running it wants to stumble if you give it much gas. Nothing else has been changed on it just whats stated above less the inner valve springs are out for breaking in the cam. Any comments or tips would be a welcome site. Thanks for reading
Posted By: Challenger 1
Re: changed cams......pops out the exhaust now - 09/11/10 09:06 PM
Quote:
Went from a hyd. to solid flat tappet cam(440). Easy swap did it before no problems just had to get different length pushrods to match the cam. Lunati cam 3 bolt with the correct comp cams 3 bolt timing chain. Put it on dot to dot nothing strange came up. Took abit longer to start but fired but had really bad popping out the exhaust. I played with timing over and over still the same. Went through all the lash again per cam in structions still no change. Checked for any type of vaccum leak, couldnt find anything. Did a complete compression test all cylinders were 175-160psi. Tore it all back down making sure I had the timing chain on right 3 different times and still the same popping. When its running higher rpms it doesnt smooth out. I checked all header tubes with a heat gun all cylinders firing. Also when running it wants to stumble if you give it much gas. Nothing else has been changed on it just whats stated above less the inner valve springs are out for breaking in the cam. Any comments or tips would be a welcome site. Thanks for reading
Weak ignition, bad pick up in dist, bad plug wire or bad cap and rotor. imo
Posted By: E85-408
Re: changed cams......pops out the exhaust now - 09/11/10 09:09 PM
Thanks for the fast response. The ignition is 2 weeks old mallory system which I made sure all ran fine before I tore it down for cam change. Since I didnt touch any of that stuff I havent checked it but I will now thanks.
Posted By: gch
Re: changed cams......pops out the exhaust now - 09/11/10 09:12 PM
Running lean maybe?
Posted By: Mopar_Country
Re: changed cams......pops out the exhaust now - 09/11/10 09:21 PM
Thinking out loud here, wires all on correctly and in the ccw rotation, dizzy not 180 out.
Posted By: Baxter61
Re: changed cams......pops out the exhaust now - 09/11/10 09:23 PM
sounds like you didnt change the valve springs and now the valves are floating.
Posted By: goldmember
Re: changed cams......pops out the exhaust now - 09/11/10 09:24 PM
Quote:
Went from a hyd. to solid flat tappet cam(440). Easy swap did it before no problems just had to get different length pushrods to match the cam. Lunati cam 3 bolt with the correct comp cams 3 bolt timing chain. Put it on dot to dot nothing strange came up. Took abit longer to start but fired but had really bad popping out the exhaust. I played with timing over and over still the same. Went through all the lash again per cam in structions still no change. Checked for any type of vaccum leak, couldnt find anything. Did a complete compression test all cylinders were 175-160psi. Tore it all back down making sure I had the timing chain on right 3 different times and still the same popping. When its running higher rpms it doesnt smooth out. I checked all header tubes with a heat gun all cylinders firing. Also when running it wants to stumble if you give it much gas. Nothing else has been changed on it just whats stated above less the inner valve springs are out for breaking in the cam. Any comments or tips would be a welcome site. Thanks for reading
Let me see if I understand,you have no inner spring installed? If so and it's a typical fast rate solid grind I would not run it over 2500rpm or so until the inners were reinstalled. It would be a good idea to confirm the seat and open loads on the springs you have. This assumes you have the lash set correctly as that could cause problems that you describe as well. Do you have the cam card info?
Posted By: E85-408
Re: changed cams......pops out the exhaust now - 09/11/10 09:27 PM
Wasnt running lean before. Didnt mess with carb just left it on manifold when I pulled it all off. Yes I checked if it was 180 out more times than I care to remember. Just pulled off the manifold again and noticed the pair 6/8 ports looked oily so going to clean everything off and reseal it. Not sure if thats it but its the first thing Ive seen wrong with it so far. Thanks again guys for the fast responses.
Posted By: 1_WILD_RT
Re: changed cams......pops out the exhaust now - 09/11/10 09:29 PM
Double check the firing order... Especially 5&7...
Posted By: moretoys
Re: changed cams......pops out the exhaust now - 09/11/10 09:31 PM
crossed plug wire?pull spark plugs.black/flooded?bigger cam = lower vacuum.Carb might need some tuning.A holley carb will most likely need a smaller power valve.did you break the cam in correctly? using the right oil/additive?Todays cams are sensative to that and a lobe can wipe out pretty easy now a days.
Posted By: E85-408
Re: changed cams......pops out the exhaust now - 09/11/10 09:34 PM
No cam card just the specs on the box. I ported the heads about a year ago with ferrea valves 10* locks and tested all the seat/open pressures. Average was 330int 340exh open 130 seat(give or take a few pounds). Yes checking the pressure without inner springs would be a good idea but I dont have the spring tester here with me. Never went above 2700 trying to break it in holding it at 2k with revs to 2700 like Ive been told. It pops even at idle(1100) its a 4 speed prefer higher idle.
Posted By: E85-408
Re: changed cams......pops out the exhaust now - 09/11/10 09:37 PM
Also the cam calls for .015 lash. Ive tried it from .022-.015 on different times it hasnt made a difference.
Posted By: Challenger 1
Re: changed cams......pops out the exhaust now - 09/11/10 10:25 PM
Quote:
Thanks for the fast response. The ignition is 2 weeks old mallory system which I made sure all ran fine before I tore it down for cam change. Since I didnt touch any of that stuff I havent checked it but I will now thanks.
What kind of dist?
Posted By: E85-408
Re: changed cams......pops out the exhaust now - 09/11/10 10:30 PM
Electronic one. Bought it new from MP few years back.
Posted By: Challenger 1
Re: changed cams......pops out the exhaust now - 09/11/10 10:32 PM
Quote:
Electronic one. Bought it new from MP few years back.
Replace the pickup in the dist, I'll bet you it's the problem.
I've seen it twice now with brand new MP dist. Cheap and easy to do, do it and let us know!
Posted By: Challenger 1
Re: changed cams......pops out the exhaust now - 09/11/10 10:35 PM
Read this thread:
web page
Posted By: mikemee1331
Re: changed cams......pops out the exhaust now - 09/11/10 10:49 PM
something is causing the valves to stick. either springs are too weak or something along those lines. if everything was fine until you changed the valve train why wouldn't the problem be in the valve train:)?
Posted By: E85-408
Re: changed cams......pops out the exhaust now - 09/11/10 10:58 PM
Didnt change valvetrain just pushrods and took inner springs out to lower pressure to break in the cam. The motor already had old isky adjustable rockers. I have a spare new pickup for the dist. which I will change out. Got it back together just letting the gasket maker cure at the moment. Again thanks for all the replies.
Posted By: mikemee1331
Re: changed cams......pops out the exhaust now - 09/11/10 11:21 PM
you did change the valve train. you changed the cam, lifters and rods. all 3 directly effect the valve train. there is a difference with how the lifter will react.
Posted By: DrCharles
Re: changed cams......pops out the exhaust now - 09/11/10 11:26 PM
Quote:
Put it on dot to dot nothing strange came up. Took abit longer to start but fired but had really bad popping out the exhaust.
I would recommend you degree the cam before chasing any other problems (especially parts that were working fine before the cam swap). Dot to dot can be WAY off. 
Posted By: E85-408
Re: changed cams......pops out the exhaust now - 09/11/10 11:45 PM
Quote:
Quote:
Put it on dot to dot nothing strange came up. Took abit longer to start but fired but had really bad popping out the exhaust.
I would recommend you degree the cam before chasing any other problems (especially parts that were working fine before the cam swap). Dot to dot can be WAY off.
I agree with you strongly but time restraints had me do other wise. Probably shot myself in the foot this time.
Posted By: E85-408
Re: changed cams......pops out the exhaust now - 09/11/10 11:50 PM
Quote:
you did change the valve train. you changed the cam, lifters and rods. all 3 directly effect the valve train. there is a difference with how the lifter will react.
I understand that effects it. I have proper lash, good compression in all cylinders and the rocker tracks the valve tip well. Also used the same size (3/8) pushrods and none were/are hitting or rubbing. If its the vavletrain what else can I check?
Posted By: buildanother
Re: changed cams......pops out the exhaust now - 09/11/10 11:52 PM
Is it actually doing alot of popping through exhaust at low load/low engine speeds?
Posted By: E85-408
Re: changed cams......pops out the exhaust now - 09/12/10 12:07 AM
With load it cant even get out of its own way. Pops at idle and higher rpms.
Posted By: buildanother
Re: changed cams......pops out the exhaust now - 09/12/10 12:14 AM
Still sounds like ignition.
Posted By: moretoys
Re: changed cams......pops out the exhaust now - 09/12/10 12:50 AM
put a vacuum guage on it.see how much it's pulling and how steady the needle is.are you running a normal elect. ign. box?? I've had an orange box go bad, Engine ran on 1/2 power.I know this could be a long shot.Possible that the cam is a firing order change cam??I forget what cyl. get changed,If I remember right 2 get swapped to prevent possible misfire,faster action.double check part#/application
Posted By: E85-408
Re: changed cams......pops out the exhaust now - 09/12/10 12:56 AM
Mallory ignition box. Only a few weeks old but that doesnt always mean working right. Trying it again in abit to see if the manifold gasket area was the problem if not in to pieces it goes and Ill go over everything again. Thanks guys
Posted By: Mopar_Country
Re: changed cams......pops out the exhaust now - 09/12/10 12:59 AM
Is it possible you have it timed up on 6 and not 1?
Posted By: E85-408
Re: changed cams......pops out the exhaust now - 09/12/10 01:04 AM
Quote:
Is it possible you have it timed up on 6 and not 1?
I have did both ways #6 TDC and dots top to bottom and #1 TDC dots top to top. I prefer #6 because its easier for me to see but yes tried both ways.
Posted By: E85-408
Re: changed cams......pops out the exhaust now - 09/12/10 02:01 AM
Fired it up still pops. Changed mallory boxes with the one on my demon along with pick up cap rotor and wires still the same. Pulled plug wire off one at a time seeing if I could pin point something but no cylinder was different from one to the next. Tearing apart and starting from sctratch again in the morning. Again thanks for all the replies.
Posted By: Mopar_Country
Re: changed cams......pops out the exhaust now - 09/12/10 02:10 AM
They do make a cam that switches 4 and 7, is it possible that you have such a cam? I know they make them for ferd and chebbies but not mopar, unless they recently started. Does your cam specs mention this at all?
Keep us posted, I'm real curious at this point.
Thanks
Posted By: moretoys
Re: changed cams......pops out the exhaust now - 09/12/10 04:11 AM
did you pull the spark plugs??black?.Usually when I see a belt/or chain off.you get inconsitant comp readings.(eg)some cyl higher than normal and some lower then normal.Is it just a popping sound or more of backfire.Backfire is usually too much fuel, not burning completely,I've used lunati stuff before,usually right on.Did you try the coil?
Posted By: mikemee1331
Re: changed cams......pops out the exhaust now - 09/12/10 04:27 AM
i'll try once more. what you are hearing is your exaust valve being sucked open when the piston is in the down (vacuum) stroke. it sounds like the top of a champagne bottle being opened. the springs hold the valve closed but only to a point (because you aren't using the inners)in the stroke and then the valve 'pops' open. it makes a popping noise and the car runs like crap.
Posted By: E85-408
Re: changed cams......pops out the exhaust now - 09/12/10 04:47 AM
Quote:
did you pull the spark plugs??black?.Usually when I see a belt/or chain off.you get inconsitant comp readings.(eg)some cyl higher than normal and some lower then normal.Is it just a popping sound or more of backfire.Backfire is usually too much fuel, not burning completely,I've used lunati stuff before,usually right on.Did you try the coil?
More like repeated backfires. It sounds like its loading up but hard to tell whether its because its running so rough or too much fuel only thing that comes to mind is if there a difference in fuel pump lobe between cams causing it to over run needles will check that in the morning. The throttle is horribly unresponsive. You cant just tap it or goose it if you try it will stumble, you have to ease into really slow to get rpms up at all.
Posted By: feets
Re: changed cams......pops out the exhaust now - 09/12/10 04:52 AM
STOP!
Several people have told you to go back and check for 1-8-4-3-6-5-7-2
You have yet to comment on that.
It's easy to screw up and we've all done it. Verify your timing before kicking yourself again.
Posted By: E85-408
Re: changed cams......pops out the exhaust now - 09/12/10 04:57 AM
Quote:
i'll try once more. what you are hearing is your exaust valve being sucked open when the piston is in the down (vacuum) stroke. it sounds like the top of a champagne bottle being opened. the springs hold the valve closed but only to a point (because you aren't using the inners)in the stroke and then the valve 'pops' open. it makes a popping noise and the car runs like crap.
Not saying your not right. I've changed/broken in a few solid flat tappet cams with dual springs and never had this issue. I normaly run without inner springs for a week then toss the inners back in. I want to break in this cam like I have the rest but I cant keep it running even remotly right to do that.
As for the break in period what would you suggest given my spring pressure as stated up the page some? I had a small block when I was younger put in a nice big cam along with some stiff single springs around the same pressure as these and within 100miles on my way home I wiped out 3 lobes and milked the car another 100 more miles on 5 cylinders to make it home. Was a bad lesson to learn but I learned it well and take more care breaking in cams but I leave the door wide open to learn new tricks of trade.
Posted By: 1_WILD_RT
Re: changed cams......pops out the exhaust now - 09/12/10 04:58 AM
Quote:
STOP!
Several people have told you to go back and check for 1-8-4-3-6-5-7-2
You have yet to comment on that.
It's easy to screw up and we've all done it. Verify your timing before kicking yourself again.
He doesn't hear you... 
Posted By: E85-408
Re: changed cams......pops out the exhaust now - 09/12/10 05:00 AM
Quote:
STOP!
Several people have told you to go back and check for 1-8-4-3-6-5-7-2
You have yet to comment on that.
It's easy to screw up and we've all done it. Verify your timing before kicking yourself again.
Sorry for not reply to every comment been a long day. Yes I've pulled all the wires off atleast 4 times and ran each one seperate to the correct cylinder.
Posted By: RapidRobert
Re: changed cams......pops out the exhaust now - 09/12/10 05:06 AM
vac leak
Posted By: GTX MATT
Re: changed cams......pops out the exhaust now - 09/12/10 05:12 AM
Double check the cam and make sure that its not for a 426 hemi
Posted By: 1_WILD_RT
Re: changed cams......pops out the exhaust now - 09/12/10 05:13 AM
Quote:
Double check the cam and make sure that its not for a 426 hemi
Ouch... Actually it wouldn't run because that would effect all cylinders equally... Which is what is odd about this whole thing cause anything related to cam timing would be effecting all cylinders too... Unless theres a problem with how the cam was ground or the condition of the lobes... The fact all cylinders show good compression makes that unlikely... Which is why I liked the firing order idea but thats been double checked sooo....
Posted By: 1_WILD_RT
Re: changed cams......pops out the exhaust now - 09/12/10 05:17 AM
Quote:
Double check the cam and make sure that its not for a 426 hemi
Ouch...
Posted By: GTX MATT
Re: changed cams......pops out the exhaust now - 09/12/10 05:22 AM
Quote:
Quote:
Double check the cam and make sure that its not for a 426 hemi
Ouch... Actually it wouldn't run because that would effect all cylinders equally... Which is what is odd about this whole thing cause anything related to cam timing would be effecting all cylinders too... Unless theres a problem with how the cam was ground or the condition of the lobes... The fact all cylinders show good compression makes that unlikely... Which is why I liked the firing order idea but thats been double checked sooo....
Good point, the compression test would have turned back something odd.
Heres and odd question open to your judgement, does it sound like an 8 cylinder engine?
Posted By: goldmember
Re: changed cams......pops out the exhaust now - 09/12/10 05:29 AM
Your NOT using the MP chart to set lash? Correct. I hope so.I assume the plug wires are installed correctly. Did you drop a plug? I'd remove them all and have a look maybe you will find a cylinder to look at more closely. You don't need a degree wheel or to remove the timing cover to confirm cam timing. PM me if you exhaust all these other simple things.
Posted By: E85-408
Re: changed cams......pops out the exhaust now - 09/12/10 05:32 AM
Yes the first split sec after it fires sounds like an 8 then it goes down hill. Another thing not sure if it will help but twisting the dist much either way has little effect not like it should which makes me think vaccum leak but cant find it even did the spray can around mating surfaces to hear a difference.
Posted By: E85-408
Re: changed cams......pops out the exhaust now - 09/12/10 05:40 AM
Quote:
Your NOT using the MP chart to set lash? Correct. I hope so.I assume the plug wires are installed correctly. Did you drop a plug? I'd remove them all and have a look maybe you will find a cylinder to look at more closely. You don't need a degree wheel or to remove the timing cover to confirm cam timing. PM me if you exhaust all these other simple things.
Ive set the lash 3-4times now I just use the starter bumper until I see the intake close one more bump and then set it. With plugs in or the starter bump rotates the motor too far. I dropped the number 6 plug more times then I care to think about but make sure I didnt smash it closed. 440 with TTI headers in a dart with inner fenders is a royal pain to change. I'll run through all again tomorrow see if I over looked anything.
Posted By: RapidRobert
Re: changed cams......pops out the exhaust now - 09/12/10 05:41 AM
IF it's a vac leak the bathtub gasket may have a leak on the underside
Posted By: Baxter61
Re: changed cams......pops out the exhaust now - 09/12/10 05:44 AM
do you have the wires in the correct order for a 440? BB dist rotate counter-clockwise, so your firing order may be correct for a SB but not BB. I just mention this because you mentioned having had SBs before. Just thinking out loud.
Posted By: goldmember
Re: changed cams......pops out the exhaust now - 09/12/10 05:51 AM
Quote:
Quote:
Your NOT using the MP chart to set lash? Correct. I hope so.I assume the plug wires are installed correctly. Did you drop a plug? I'd remove them all and have a look maybe you will find a cylinder to look at more closely. You don't need a degree wheel or to remove the timing cover to confirm cam timing. PM me if you exhaust all these other simple things.
Ive set the lash 3-4times now I just use the starter bumper until I see the intake close one more bump and then set it. With plugs in or the starter bump rotates the motor too far. I dropped the number 6 plug more times then I care to think about but make sure I didnt smash it closed. 440 with TTI headers in a dart with inner fenders is a royal pain to change. I'll run through all again tomorrow see if I over looked anything.
Change the number 6 plug if you have kept up with it and not moved it to another hole.. Plugs are easily damaged without smashing them closed. Try it,easy and cheap.
Posted By: jt1
Re: changed cams......pops out the exhaust now - 09/12/10 12:07 PM
Quote:
BB dist rotate counter-clockwise, so your firing order may be correct for a SB but not BB.
Double check this, it's bit me before. Almost unbelievably, the thing would run but very poorly, firing order correct but direction of rotation wrong.
John
Posted By: B5 Bee
Re: changed cams......pops out the exhaust now - 09/12/10 06:06 PM
Quote:
Ive set the lash 3-4times now I just use the starter bumper until I see the intake close one more bump and then set it. With plugs in or the starter bump rotates the motor too far.
This isn't the correct way to set valves.
The MP chart works with sold flat tappet and small roller cams.
Without the MP chart;
Set the int just as the exh begins to open.
Set the exh just before the int fully closes.
Posted By: E85-408
Re: changed cams......pops out the exhaust now - 09/12/10 10:58 PM
Went through everything again...you name it I checked it. After a full body fit I had an idea I yanked the pvc tube off the back of the carb and fired it up. There was zero difference. I got the thickest oil out I could find and covered the intake mating surfaces. Fired it up and watched the oil get sucked it. New gasket should be here in awhile.
Big thanks for all the replies.
Posted By: E85-408
Re: changed cams......pops out the exhaust now - 09/13/10 06:48 PM
Changed intake gasket and runs like a champ. Finally got to break in cam and put some miles on it. The popping was gone right after I changed the gasket. Sad to have missed monster mopar weekend(was suppose to race) but glad its running again.